A variety of hand-held surgical instruments have been proposed and/or are in use today for effecting a variety of surgical procedures or other operations that are performed upon human or animal anatomical structures, such as bone and tissue, including skin, muscle, and fascia. Some of these instruments are also used to effect certain operations with, or on, foreign bodies or prosthetic devices that may be implanted in, or carried by, a human or animal subject. Examples of the above-described instruments include instruments for applying ligating clips to blood vessels, bone crushing instruments, pin cutting instruments, instruments for applying staples or other types of fasteners to tissue, and the like.
Many of these types of instruments are held in one hand by the surgeon and include one or more movable operating elements or members (e.g., crimping or gripping jaws) which are located toward an end of the instrument that is spaced from, or remote from, the surgeon's hand. Typically, such an instrument includes an operating handle mechanism, which may be a reciprocative element, a single lever, a pair of scissors-type levers, or other suitable mechanism. The operating member or members are connected through mechanical linkages to the handle mechanism. Manipulation of the handle mechanism by the surgeon causes the desired movement of the operating member or members so as to effect the desired operation, such as applying a ligating clip to a blood vessel, cutting a pin, crushing a bone, inserting a staple or fastener into tissue, and the like.
A method has been proposed for using an instrument or device for closing wounds or surgical incisions in mammalian tissue with fasteners made from flexible and resilient biocompatible material which may be either absorbable or nonabsorbable in body tissue. One such type of device for applying such a fastener to tissue is generally disclosed in U.S. Pat. No. 4,006,747.
The device disclosed in U.S. Pat. No. 4,006,747 generally includes a slotted hollow needle in which is carried a portion of the fastener, a rigid plunger for pushing the fastener along the needle and into the tissue, and a mechanism for moving the plunger into the needle and then for withdrawing the plunger from the needle.
Other devices of the type disclosed in U.S. Pat. No. 4,006,747 suitable for use in applying various types of fasteners are disclosed in U.S. Pat. Nos. 3,470,834, 3,103,666, 2,069,878, 3,494,004, 3,399,432, 3,518,729, and U.S. Pat. No. Des. 313,418.
Other devices for applying fasteners in a non-surgical situation are disclosed in U.S. Pat. Nos. 3,209,422 and 3,733,657.
Prior to the disclosure in U.S. Pat. No. 4,006,747 of the method for applying a fastener simultaneously through a needle and tissue, procedures for the manual application of sutures or fasteners through tissue with needles or needle-like elements were known. Examples of such sutures and needles are disclosed in U.S. Pat. Nos. 3,636,956, and 3,716,058.
In none of the above-discussed procedures or devices is a hydraulic actuating mechanism used to effect the desired operation, such as placing a fastener through tissue. The inventors of the present invention have determined that it would be desirable to provide a type of hydraulic actuating mechanism for use in a wide variety of surgical instruments, including in the fastener applying devices described above.
Further, it would be beneficial to provide such a hydraulic mechanism that could either amplify the movement of the instrument operating member relative to the handle movement or amplify the force of the operating member relative to the force applied at the handle. In addition, it would be desirable to provide such a hydraulic actuating mechanism with means for automatically returning the instrument handle to an unactuated or released position.
Also, it would be advantageous if instruments of the class described could be provided with the hydraulic actuating mechanism of the type described wherein the hydraulic actuating mechanism was relatively small and compact so as to permit incorporation of the mechanism in a housing that could be easily grasped and manipulated with one hand by the surgeon.
With such a hydraulic mechanism, the inventors have found that it would be desirable to arrange the hydraulic cylinder and piston components within the housing so as to be operably engaged with the handle through a minimum of mechanical connections or linkages.
It would be also beneficial if the hydraulic actuating mechanism could be made from relatively inexpensive materials, along with the other instrument components, so that the instrument, after being initially provided to the surgeon in a sterile package, can be disposed of after one use. With such a disposable instrument, it would be desirable to provide a hydraulic actuating mechanism that could be fabricated, along with the other components of the instrument, from non-toxic materials that would have little or no deleterious effects on the environment as a result of proper disposal of the instrument after use.